Inhibiting agent for gasoline and method of producing same



Patented Sept. 3, 1940 UNITED STATES PATENT INHIBITING AGENT FOR GASOLINE AND METHOD .OF PRODUCING SAME of -D elaware N Drawing.

Application October 23, 1937,

Serial No. 170,598

6 Claims.

otherwise detract from the quality of the gasoline.

Various methods have been proposed to remove these gum-forming constituents from the gasoline and various agents have been suggested for inhibiting their formation.

One of the objects of our invention is to provide an improved addition agent for gasoline which will inhibit the formation of gum.

A further object of our invention is to provide 5 an improved inhibitor of the character described whichjs relatively inexpensive and which may be obtained from petroleum sources.

A further object of our invention is to provide a new and improved method of refining hydrocarbon oil such as kerosene and heating or furnace oil which will not only improve the oil so refined with respect to its burning properties, but which will also produce as a product of said re fining treatment, a material which is of particular value for inhibiting the formation of gums in gasoline.

A further and more specific object of our invention is to provide a new and improved process for. forming a product which is of particular value as an inhibiting agent for gasolines."

Various other objects and advantages of our invention will'be apparent from the more detailed description hereinafter.

, In accordance with our invention, we first sub ject a petroleum oil, which is preferably a distillate having a boiling range somewhat above the light naphtha range of about 250 F. and which may be heavy naphtha, kerosene, furnace oil or light gas oil, to treatment with a sodium hydroxide solution having a concentration ranging salts into the original acidic compounds.

from about 40 B., preferably between -35 B. The petroleum oil of proper boiling range, treated with said caustic soda solution, may be a virgin distillate from a crude source or it may be a distillate resulting from the thermal decompo- 5 sition of petroleum hydrocarbons. The petroleum oil may be untreated, or it may have been previously subjected to refining such as acid, re running or sweetening treatment or combinations of these.

The caustic solution reacts with certain organic acids and acidic compounds present in the'oil to form salts which precipitate out in the form of a dark oily layer.

The dark oily layer is then separated from the remainder of the oil and acidified by means of a weak acid solution, such as a weak sulphuric or hydrochloric acid solution, carbon dioxide or gases containing. carbon dioxide to convert the Acidification with carbon dioxide is preferred since no control is necessary to avoid an excess and the acidified product contains less water than when using dilute mineral acids. Moreover, the use of a weak acidifying agent such as CO: permits selective acidification of the salts. Also the use of C02 avoids the formation of polymer products which may result from the use of mineral acids.

Thisextract appears to be composed largely of alkylated hydroxyl aryl compounds and other compounds of more indefinite acidic nature having an alkylated cyclic structure. These compounds have been found to have particular value as addition agents for inhibiting the formation of gum in gasoline. To this end, they may be added to the gasoline in amounts varying from 0.1 to about 1.0 percent of the extracted material. It has been found that this material has a stabilizing effect on the gasoline, retarding the formation of objectionable gums. This extract has been found particularly eifective as an inhibitor when the concentration of the alkaline solution is regulated within the prescribed limits hereinbefore pointed out. When weaker solutions are employed, the extracted product does not have the same beneficial properties. If

stronger solutions are employed, difficulty is encountered in eifecting the separation due to emulsification of the oil and the caustic solution.

While the crude extract may be employed as a gum inhibitor in'gasoline, it is preferred to further purify the product by vacuum distillation at a temperature of about 400 F. removing about per cent as overhead products and discarding the final twenty per cent. This distillation has been found to materially reduce the sulfur content.

It has been found that kerosene, furnace oil and other burning oils are materially improved by the alkaline treatment of the character described. The oil so treated has better burning properties, in that it burns with a clearer flame and is less likely to smoke, is of better color and more stable than the original untreated oil. Thus, in accordance with our invention, we are able to extract from light distillate oils, such as heavy naphtha, kerosene and furnace oils, a byproduct which is of particular value as an inhibiting agent' for gasoline without detracting from, and in fact improving, the quality of the oil so treated.

The amount of alkaline solution employed per volume of oil may vary over relatively wide limits depending on the character of oil treated. In most cases, from about .2 to about .5% of sodium hydroxide solution based on volume of oil treated will be adequate to effect the desired treatment and no particular advantage will be gained by using a greater proportion, while an amount below .2%, for example, will not ordinarily effect the desired improvement in the oil treated.

As an aid in carrying out our invention to obtain the greatest benefits therefrom, the following example will be useful, it being understood that the values givenare illustrative rather than limitative;

Ewample.A heating oil fraction of petroleum boiling between 400-600 F. was caused to react with a solution of sodium hydroxide having a gravity of 40 B. The volume of sodium hydroxide solution employed was .15 pound per barrel of oil treated.

After agitating the oil with the sodium hydroxide solution, the mixture was allowed to settle and a dark oily layer was formed. .This layer was separated from the remainder of the oil and acidified with C02. The acidified extract was then redistilled under vacuum at 420 F. until 80 per cent of the product was recovered as a distillate. This distillate was then added to separate samples of a gasoline having a breakdown time of 1.8 'hours in amounts of one, two and'three pounds-per1000 gallons of oil. The breakdown period of the respective samples was 2.5, 3.5 andv 6.8 hours respectively. Similar amounts of commercial t'ri-cresol resulted in breakdown periods of 3.0, 2.9 and 4.3 hours respectively.

' The breakdown is 'a measure of the induction period or the period which elapses before oxidation occurs. It is determined'by introducing twenty-five cc. of the gasoline into a test tube which is inserted into a bomb. The bomb is placed under pounds oxygen pressure at room temperature and then heated to 13 temperature of 212 F. The time elapsed before. there is a two pound drop in pressure-as measured from the maximumpressure attained in the bomb is recorded as the breakdown period.

The above results show,-therefore, that oxidation of gasoline is materially retarded by the addition of the extract to the gasoline.

The remaining heating oil, after treatment with the caustic sodium hydroxide solution and the separation of the extract resulting therefrom was then compared with the original heating oil fraction without treatment with sodium hydroxide, with the following results:

Untreated Treated Color (R) 10% 12% Color hold, 16 hrs. 212 F. (R) 2 2 Bomb oxidation test: Total acidity. cc.

O.IN NaOH 9. 10 7. 6 Burner test:

Hard carbon, #[1000 gals; 0. 51 0. 36 Soft carbon, #11000 gals 2. 46 2. 12

From the foregoing, it is evident that our invention performs atwo-fold function. First, it produces a marked improvement in the oil treated and, second, it forms a product of the treatment which, when added to gasoline, mate-1 rially improves the stability thereof.

While we have described the use of sodium hydroxide for the treatment of the oil to produce the extract, other alkaline or basic materials may be employed in its stead. In such case, the hydroxyl ion concentration of the basic material used should be equivalent to the sodiumcharacter, it will remain in the pores of the wood indefinitely.

We are aware that it has heretofore been proposed to subject petroleum oil to treatment with caustic solutions of varying concentrations, but we believe that we are the first to' discover that by treating the selected fractions of oils with caustic solutions of the concentration herein described, there can be produced an extract product which is valuableas an addition agent for gasoline and as a wood preservative.

Having described these specific embodiments, it is understood that our invention embraces such other variations and modifications as come within thespirit and scope thereof. further understood that it is not our intention to unnecessarily limit the invention or to dedicate any novel features thereof.

What we desire to have protected by Letters Patent is:

l. A process for the recovery of motor fuel inhibiting agents which comprises treating a heating oil petroleum fraction boiling between about 400 F. and about 600 F. with an aqueous sodium hydroxide solution of about 40 B. in an amount of about 0.15 pound per barrel of oil treated, separating an oily layer from" the oil treated, acidifying said layer with carbon dioxide, distilling the acidified oily layer extract under vacuum at about 420 F., and recovering about 80% of said extract as a distillate.

2. A process as in claim 1 wherein the 80% distillate is added to a motor fuel.

3. A process .for the recovery of motor fuel inhibiting agents which comprises treating a heating oil cracked petroleum fraction boiling between about 400 F. and about 600 F. with an 1 alkaline aqueous solution of an alkalinity qorre- It will be between about'0.2% and-about 0.5% based on'7 the volume of the oil treated, separating an oily layer as an extract from the oil treated, selectively acidifying the extract, and recovering the phenolic constituents fromthe acidified extract.

4. A process for the separation of phenolic constituents from heating oils obtained from cracked petroleum fractions and having a boiling range between about 400 F. and about 600 E, which. comprises treating said heating oil with an aqueous caustic soda solution of between about 30 B. and about 40 B., separating the resultant oily layer extract from the oil treated, and acidifying said extract to liberate the phenolic content thereof.

5. A process which comprises treating a petroleum oil boiling between about 400 F. and about 600 F. with an alkaline solution equivalent in alkalinity to a sodium hydroxide solution of be- 600 F. with a caustic soda solution of between about 30 B. and about 40 B., separating the resultant extract from the oil treated, passing carbon dioxide through said extract, subjecting the resultant acidified extract to distillation to form a distillate fraction and a residue fraction,

and adding the distillate fraction to gasoline to 15 of gum therein. ALBERT J. SHMIDL. JOSHUA M. SMITH. v

inhibit the formation 

